emmerling



Feb. 9, 1960 R. w. EMMERLING 2,923,997 SAGGERS Filed July 9. 1956 2Sheets-Sheet l INVENTOR ATTORNEYS 1950 R. w. EMMERLING 2,923,997

SAGGERS Filed July 9. 1956 2 sh t -sh t g 1N VENTOR wf gZwa ATTORNEYSUnited States Patent- SAGGERS Ralph W. Emmerling, Canton, Ohio, assignorto United States Ceramic Tile Company, Canton, Ohio, a corporation ofOhio Application July 9, 1956, Serial No. 596,663

7 Claims. (Cl. 25-153) This invention relates to a device for exposingceramic ware to the heat of a kiln in the heat treatment of the ware andmore particularly relates to a device for supporting ceramic tile duringa glazing operation.

The glazing of ceramic tile is a quite old process and a large number ofsupport devices, commonly known as saggers, have been devised forsupporting the tile in the kiln. Generally speaking the saggersheretofore utilized have consisted of a vertical support holding aplurality of parallel superposed ceramic plates between which the tilesare inserted. While these devices have long been used to produce more orless satisfactory glazed tile they are subjected to a number ofdisadvantages which have the effect of raising the cost of the tile.

The current tendency towards the mass production of homes and the massproduction of all elements of con struction used therein has given addedimportance to small savings in cost of mass produced items such asglazed tile. Thus, a completely satisfactory sagger should not only beconstructed of relatively low cost materials, but it should be of such anature that the sagger itself can be constructed in a minimum time witha minimum amount of labor and its construction should facilitate therapid loading of tiles to be glazed with a minimum number 0 rejects dueto damage to the glazed surface.

In order to utilize the kiln capacity to a maximum extent the ratio ofthe weight of the sagger to the weight of, the ware and the ratio of thevolume of the sagger to the volume of the ware should be as low aspossible and the refractory of the sagger should have a high thermalconductivity to permit better absorption and dissipation of heat forfaster cycling of the kiln. The sagger design should be such thatheating and cooling by convection is facilitated and every advantage ofradiation should be taken.

It is accordingly a primary object of the present invention to providean improved sagger which facilitates the rapid and economical productionof glazed tile.

It is another object of the invention to provide an improved saggerwhich permits rapid loading without damage to the glazed surface of thetile.

It is another object of the invention to provide an improved saggerhaving low ratios of the weight of the sagger to the weight of the wareand of the volume of the sagger to the volume of the ware.

It is another object of the invention to provide an improved saggerhaving a high thermal conductivity and having a hot and cold mechanicalstrength which permits the use of thin sections.

It is another object of the invention to provide an improved saggerwhich is so constructed as to permit rapid heating and cooling of thetiles by convection and to also permit expansion and contraction of thesagger shelves without fracture.

It is another object of the invention to provide an improved saggerformed of a refractory material which provides high mechanical strength,high thermal conductivity and high hot load strength.

2,923,997 Patented Feb- 9, 1960 These and further objects and advantagesof the invention will become apparent upon reference to the followingspecification and claims and appended drawings wherein:

Figure 1 is a perspective view of a sagger constructed according to oneembodiment of the invention; I

Figure 2 is a perspective view of one of the support posts of the saggershown in Figure 1;

Figure 3 is a vertical elevation of the support post of Figure 2 showingthe edge thereof;

Figure 4 is a perspective of one of the intermediate shelves of thesagger of Figure 1;

Figure 5 is an exploded view of a sagger constructed according toanother embodiment of the invention; and

Figure 6 is a perspective view of one of the intermediate shelves of thesagger of Figure 5. I

Referring to Figures 1 through 4, a sagger generally indicated at 10 iscomprised of a rectangular bottom shelf 12, four support posts 14, 16and 18 and a rectangular top shelf 20. All of the support posts areidentical and are comprised of elongated rectangular members havingslots 22 in one edge thereof and having radius corners 24 at the edgesof the slots. As is seen in Figure 3, one flat side of the support postsis provided with a series of shallow V corrugations 26 and the apexesof'the V- shaped corrugations fall substantially equidistant of theslots 22. Reference to Figure 1 will show that the sup port posts 14 and16 which are at the back of the sagger are mounted with their flatuncorrugated surfaces contiguous to the long edge of the bottom shelf 12while the other two support posts 18 are mounted with their flatuncorrugated surfaces contiguous the short edges of the bottom shelf 12.A plurality of intermediate shelves 28 cut away at 30 and 32 to receivethe unslottedportions of the support posts are mounted within the slots22. A pair of strips 34 are mounted along the lower edges of thelowermost shelf 12 in order that the superimposed load which occurs uponstacking the saggers may be concentrated on the four corners toeliminate transverse strains.

The support posts are cemented at their tops and bot-' toms to the topand bottom plates 20 and 12 respectively,: but the intermediate plates28 are retained within the sup-.

port posts merely by the cooperating shapes of the shelves and supportposts, all supports being provided by the: slots. This structure permitsfree expansion and contract-A tion of the intermediate shelves during acycle of opera tion and prevents breakages which have heretoforeoccurred in rigid sagger assemblies. The radius edges 24 of] the slots22 guide the intermediate shelves into the slots during assembly of thesagger. to expedite sagger con-1 struction and the identical nature ofall support posts.

further minimizes expense and expedites sagger assembly.

The V-shaped corrugations in the flat surfaces of the. posts prevent theglazed surface of the tile from contact ing the posts and therebyprevents any marring of or damage to this surface. The particular shapeof the sagger, and particularly the arrangement of the support posts,facilitates sagger loading in that the operator can merely push theglazed tiles onto the shelves from the front of the sagger until therear edge of the tiles strikes.

the inner V-shaped surfaces of the support posts 14 and 16. Because ofthe V-shape of the posts this contact does;

not damage the tile but immediately informs the operator that the tileis properly placed in the sagger and no further alignment is necessary.The sagger shown in Figure 1 is constructed to accept two tiles on eachshelf although is open so that heating and cooling through convection isfacilitated.

In order to obtain the desired mechanical strength to permit such thinshelves and to provide the desired high thermal conductivity it has beenfound that the following refractory material is advantageous:

Percent Calcined alumina 72.5 Ray 48 mesh kyanite 2.5 Ball clay (airfloated) 25.0

The refractory is prepared by grinding a 12,000 lb. batch of theforegoing formula for 10 hours in a ball mill with 1 020 gallons ofwater. After the grinding 99.5% of the wet ground body will pass a 200mesh standard screen (screenopening .0029 inch) and the batch is thenfilter pressed and the filter cakes dried to zero moisture; The dryfilter cakes are then crushed, pulverized through an impact mill andscreened to minus 16 mesh (screen opening .0465 inch).

A typical screen analysis of the screened body is as follows? Four 100pound batches of the screened body with an addition of 0.5% organicbinder and 4.0% water are then mixed in a muller type mixer for 10minutes. The body is next pulverized in an impact mill and placed instorage ready for use.

A typical screen analysis of the body prepared for pressing is asfollows:

Opening, Percent Percent Screen Mesh inches on Screen Through Screen Inpressing the die cavities of a friction press are filled with materialwhich is then pressed with four impact blows. The pressed pieces aredried at 200 F. in a periodic convection type drier for 12 hours and arethen set'on kiln bars in a vertical position and fired in a continuousgas fired tunnel kiln to 2550 F. on a 48 hour cycle. The pieces areinspected for cracks by sounding and warpage is checked by a gage setfor a tolerance of plus or minus .002 inch per inch of strength.

Turning to Figures and 6 there is shown another embodiment of theinvention wherein a sagger indicated generally at 36 is comprised of apair of side support plates 38 and 40 which are tenoned to top andbottom plates 42 and 44. The top and bottom plates 42 and 44 areprovided with mortises 46 which mate with tenons 48 on the side plates38 and 40 and these members are cemented together.

The inside surfaces of the side plates 38 and 40 are divided into twoequal sections by means of short vertical inwardly extending Wallportions 50' and 52. The inner surface of side plate 38 to the right ofwall portion 50 is provided with a plurality of horizontal slots 54which are adapted to receive one edge of shelves 56. The other side ofthe inner surface of the side plate 38 to the left of wall portion 50 isprovided with a plurality of horizontal ridges 58 having an uppersurface 60 which "4 is at the same level as the lowermost edge 62 ofslot 54.

Extending from the inner surface of the left end of the side plate 38atop the ridge surfaces 60 are a plurality of arcuate projections 64which terminate short of the undcrsurface of the overlying ridge. Thatis to say the upper surface 66 of projection 64 is spaced from theundersurface of the ridge 58 by a distance which is greater than thethickness of the shelf 56 and the upward heighth of the projections isless than the combined thickness of a shelf and tile laying therein. Ateither end of the ridges 58 are projections 68 which are approximatelyone half of the length of the projections 64 and which are provided withfiat edges 70.

Referring to Figure 6 the sides of the shelves 56 are shaped to matewith the projections 64 and 68 and are assembled in the sagger byinserting one edge 72 into the slot 54 while the shelf is maintained ina cocked position so that the other edge 72 is received in the spacebetween the upper surfaces 66 of the projections 64 and 68 and the loweredge of the ridge 58. The shelf is slid into the sagger until its inneredge strikes the wall portions 50 and the edge above the projections 64and 68 is then lowered to rest upon the surfaces 60 of ridges 58. Whenin this position the shelf is locked by projections 64 and 68 and neednot be cemented into position, thereby permitting free expansion andcontraction without damage to the sagger.

The surfaces of wall portions 50 and 52 are corrugated, that is the wallportions are tapered from a thick section 74 which is generally on alevel with the shelves to a thin portion 76 so as to prevent damage tothe glazed surface of the tile upon its insertion into the sagger. Thesurfaces 77 between slots 54 are similarly tapered for the same reason.It will be apparent that the inner surface of side plate 40 oppositeprojections 64 and 68 on side plate 38 is provided with grooves 54,While the inner surface of side plate 40 opposite the inner surface ofside plate 38 having grooves 54 is provided with projections 64 and 68.The inner end edges 78 of side plates 38 and 40 at the slotted sidesthereof are radiused or beveled to permit rapid and easy insertion ofthe tile. The arcuate projections 68 on the inner surface of theopposite side plate serves this same function.

The refractory material utilized possesses a high hot and cold strengthand thus permits the use of thin shelves with a resultant low ratio ofthe weight of the sagger to the weight of the ware and a low ratio ofthe volume of the sagger to the volume of the ware. This materialfurther possesses a high thermal conductivity which permits a fastcycling of" the kiln and allows the refractory to heat rapidly toprovide increased benefits from radiation. The high hot load strength ofthe refractory provides exceptional resistance to slumping at elevatedtemperatures. The construction of the sagger embodies good stability formultiple stacking in the kiln and the combination of bonding andmechanical locking of the plates permits mechanical loading andunloading of the saggers into the kiln.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

l. A sagger comprising a bottom plate and a top plate and verticalsupport means at both sides of said plates securing said platestogether, a plurality of slots in said support means extending to thevertical edges thereof, and shelves mounted in and supported by saidslots, said shelves having cutaway portions interlocking with portionsof said support means to prevent sliding removal of said shelves, saidshelves being very thin and being comprised of calcined alumina, kyaniteand ball clay, said support means including a corrugated surfaceparallel to the longer edges of said shelves for limiting the depth ofinsertion of tile supported on said shelves, said corrugations impartinga maximum thickness to said support means at the level of said slots,the recessed portions of said corrugated surface occurring intermediatesaid slots to provide clearance for the glazed surface of said tile.

2. A sagger according to claim 1 wherein said support means are cornerposts, said posts comprising elongated members having slots in one edgethereof and having one side thereof with an undulating surface, two ofsaid posts being mounted with said slots facing inwardly of said saggerin the same direction and the other two of said posts being mounted withsaid slots facing inwardly of said sagger in a direction perpendicularto said first direction.

3. A sagger comprising a bottom plate and a top plate and a pair ofparallel side plates joining said bottom and top plates, each of saidside plates having a plurality of parallel slots in the inner surfacethereof, a plurality of parallel ridges on the inner surface of eachside plate, said ridges on each plate being opposite said slots in theother plate, -a plurality of protrusions from the inner surface of eachplate extending upwardly from said ridges, and a plurality of shelveshaving one edge thereof received in said slots and the other edgethereof resting on said ridges, said other edge being shaped to matinglyinterlock with said protrusions.

4. A sagger comprising a bottom plate and a top plate and a pair ofparallel side plates joining said bottom and top plates, each of saidside plates having a plurality of parallel slots in the inner surfacethereof, a plurality of parallel ridges on the inner surface of eachside plate, said ridges on each plate being opposite said slots in theother plate, the slots and ridges in each side plate being separated bya vertical wall portion extending from the inner surface of the plate, aplurality of protrusions from the inner surface of each plate extendingupwardly from said ridges, and a plurality of shelves having one edgethereof received in said slots and the other edge thereof resting onsaid ridges, said other edge being shaped to matingly interlock withsaid protrusions.

5. A sagger comprising a bottom plate and a top plate and a pair ofparallel side plates joining said bottom and top plates, each of saidside plates having a plurality of parallel slots in the inner surfacethereof, a plurality of parallel ridges on the inner surface of eachside plate, said n'dges on each plate being opposite said slots in theother plate, the slots and ridges in each side plate being separated bya vertical wall portion extending from the inner surface of the plate, aplurality of protrusions from the inner surface of said plate extendingupwardly from said ridges, and a plurality of shelves having one edgethereof received in said slots and the other edge thereof resting onsaid ridges, said other edge being shaped to matingly interlock withsaid protrusions, said protrusions extending upwardly from said ridges adistance less than the combined thickness of a shelf and a tile mountedthereon.

6. A sagger as set out in claim 4 wherein the endmost protrusions oneach ridge are of a different shape from the remaining protrusions andhave one substantially vertical surface substantially perpendicular tosaid side plates.

7. A sagger as set out in claim 5 wherein said shelves are very thin andare comprised of calcined alumina, kyanite and ball clay.

References Cited in the file of this patent UNITED STATES PATENTS984,593 Oestreicher Feb. 21, 1911 1,273,397 Neill July 23, 19181,802,245 Foretich Apr. 21, 1931 1,841,641 Schreiber Jan. 19, 19321,969,126 Forse Aug. 7, 1934 2,118,641 Diamond May 24, 1938 2,246,448Mahan June 17, 1941 2,297,286 Book Sept. 29, 1942 2,733,497 CriswellFeb. 7, 1956 FOREIGN PATENTS 636,515 Great Britain May 3, 1950CERTIFICATE OF CORRECTION Patent No, 2323 997 February 9, 1960 Ralph WEmmerling Column 3 line 9 for "Ray" read Raw line 45, in the table thirdcolumn thereof under the heading "Percent on Screen"' second line for2038" read 0 38 Signed and sealed this 23rd day of August 1960,

(SEAL) Attest:

KARL Ha AXLINE ROBERT c. WATSON Attesting Officer Commissioner ofPatents

